A petition called on Supreme Court Chief Justice John Roberts to clarify ethics requirements for justices' public appearances, ahead of a scheduled speech by Justice Neil Gorsuch at Trump International Hotel.

"We believe that Chief Justice Roberts has the authority — and the responsibility — to discourage his colleagues from participating in these types of events," the petition read. "We, the undersigned, call on the chief justice to delineate clearer ethics rules for the justices' public appearances."

At issue is Gorsuch's scheduled speech at the Trump International Hotel in Washington. Gorsuch, appointed to the court by Trump this year, is the keynote speaker for the Fund of American Studies' Defending Freedom Luncheon on Thursday. The event is invite-only.

"A Trump appointee speaking at a Trump hotel as the court considers a Trump case unnecessarily invites reproach of our sole functioning branch of government and hurts its legitimacy," Gabe Roth of Fix The Court said. "Justices should not only seek out less controversial venues, they should also try to address ideologically diverse groups, as the impact of seeing the country's leading jurists appear before contrarian audiences would go far beyond whatever words they'd share."

Since the news first broke about the speech, groups have called on Gorsuch to cancel.

One letter, sent in late August, cited the code of conduct for U.S. judges: "A judge 'should maintain and enforce high standards of conduct and should personally observe those standards, so that the integrity and independence of the judiciary may be preserved.'"

The appearance will also come after Gorsuch was criticized for appearing with Senate Majority Leader Mitch McConnell in Kentucky over the weekend.

This Supreme Court handout photo shows President Trump and Gorsuch at a courtesy visit in the Justices' Conference Room prior to the investiture ceremony on June 15, 2017.
Fred Schilling, AFP/Getty Images

President Trump watches as Justice Anthony Kennedy administers the oath of office to Neil Gorsuch as an associate justice of the Supreme Court in the Rose Garden of the White House on April 10, 2017.
Mandel Ngan, AFP/Getty Images

In this photo provided by the Supreme Court's Public Information Office, Chief Justice John Roberts and fellow justices watch as Neil Gorsuch signs the constitutional oath after a private ceremony on April 10, 2017, at the Supreme Court.
Franz Jantzen, AP

Gorsuch speaks alongside his wife, Louise, and President Trump in the East Room of the White House on Jan. 31, 2017. "It is the role of judges to apply, not alter, the work of the people’s representatives," he said in his remarks. "A judge who likes every outcome he reaches is very likely a bad judge, stretching for results he prefers rather than those the law demands."
Carolyn Kaster, AP